The content of arsenic from fluosilicic acid exceeded 10-5, in order to ensure the quality of anhydrous hydrogen fluoride,arsenic must be removed, while fluosilicic acid was maked into anhydrous hydrogen fluoride. Arsenic was removed by chemical precipitation method , and an inquiry was made into the effect of the types of arsenic removal, amount, reaction time, reaction temperature, aging time on the remnants of arsenic. Experiment result showed that arsenic could be less than 10-6 after that fluosilicic acid was purified by chemical precipitation method,and the content of arsenic from production of anhydrous hydrogen fluoride was lower than 8×10-6 and arsenic content had been reached the quality requirements of developing downstream products of anhydrous hydrogen fluoride.Therefore, the method of chemical precipitation could remove effectively arsenic from fluosilicic acid.